This paper describes and analyzes the occurrence and extent of oppositions initiated
against plant biotechnology patents granted by the European Patent Office (EPO). The
opposition mechanism is a legal procedure that allows any third party to challenge the
validity of patents awarded by the EPO. Results indicate that the opposition rate is far
greater in plant biotechnology than in other emerging industries. Consistent with
theoretical predictions, the empirical findings suggest that opposed patents are
disproportionately those that score high on features that proxy for their “value” or
“quality”. In contrast to previous findings, however, the results show that large-volume
applicants are more likely to be opposed. Because the boundaries of plant biotech
patents are ill-defined, large patent portfolios do not promote cooperative behavior such
as licensing or settlements. The analysis rejects the hypothesis that awardees are subject
to “nuisance” or “frivolous” oppositions. Instead, the opposition procedure serves as an
error correction mechanism.